Testimony wrapped up Thursday with the lead investigator in the murder case reading six letters written by Christopher Leclair in prison.

In the letters, Leclair said his wife Karen killed herself on the back of the Doris M, and he tied her to an anchor and threw her into the lake because he did not want anyone to know that she took her own life.

In one of the letters, Leclair said he went scuba diving the next day in an attempt to find Karen's body before calling the Coast Guard.

Leclair said he then went out again and actually found Karen but was called off the lake by police before he could recover her body.

The woman who was dating Leclair at the time of his wife's death took the stand to testify Thursday.

Tracy Butler said she had been pressuring Leclair to leave his wife Karen, so they could get married and start a life together.

Butler testified that she gave him an ultimatum and threatened to call Leclair's wife if he did not tell her.

Butler said she and Leclair have been dating off-and-on since 2013, and at one point, they lived together for 8 months in Albion.

Text message conversations between the two in the days leading up to the murder were also shown in court.

Both the prosecution and defense agree Leclair was having an affair.

The prosecution said he killed Karen to cover up his double life.

The Allegheny County medical examiner also testified for the defense Thursday. He said based on his review, the wounds to Leclair's head were self-inflicted.

Under cross-examination, the medical examiner would have taken other factors into consideration if he conducted the autopsy himself.

Closing arguments are set for Friday morning.